Only two species of lichen genus Diploschistes Norman have been documented in Thailand, Diploschistes actinostomus (Ach.) Zahlbr. and D. cinereocaesius (Sw. ex Ach.) Vain. Diploschistes scruposus (Schreb.) Norman is reported here as a new record. The species is characterised as having saxicolous habit, urceolate ascomata and sub-muriform ascospores. Descriptions, illustrations and a key to species are provided together with their distribution and ecology.